Telephone-exchange system.



Patented Apr, 16, 1918.

C. W. KECKLER.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JULY 12.1917.

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CHARLES W. KECKLER, or nnwennnnw Jensen, assrenon To wnsrnnn ELECTRIC COMPANY, INCORPORATED, or new roan, n. Y.,;A conronarron or NEW YORK.

TELEPHONE-Excitat on SYSTEM.

To all whom it may concern: 1

Be it known that I, CHARLES IV. KECKLER, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have inventedcertainfnew and useful Improvements in Telephone-Ere change Systems, of which the following s a full, clear, concise, and exact description.

This invention relates to telephone eX- changesystems and has for its' ob ]ect the production of such a system in wl11ch 1t is impossible for an operator to l sten 1n on a connection established between two telephone lines and in which it is impossible to establish a connection between two telephone lines using portions of two connecting circuits.

In accordance with a feature of this invention, a central office connecting circuit joining two telephonelines is provided with means whereby, when an operator controlled switch is actuated to connect an operators telephone set with one end of the connecting circuit, the other end is thereupon shortcircuited. I

In accordance with another feature of this invention, the connecting circuits are provided with means whereby, when two operator controlled switches of different conators telephone set.

For a more complete understanding of this invention, reference should be had to the following description considered in connection with the accompanying drawing, wherein Figure 1 shows a telephone exchange system containing one embodiment of this invention; and Fig. 2 shows a modified form thereof.

.In Fig. 1 there are'showntwo telephone lines A and B, which extend from subscribers stations to a central office, at which is located a cord circuit C employed for connecting together the two telephone lines.

Forconvenience only, these two lines and the one cord circuit are shownbut it is to be understood that many suchlines and several suchcord circuits may be and usually are provided in the same central office. 3

Assuming that the answerlng end of the cord circuit C is connected with the answering jack of telephone line'A, the; calling plug of cord circuit C 1s connected with the Specification of'Letters Patent, Patented Apr. 16,1918. Application filed July 1a, 1917. serial No. 180,117.

answering jack. of line B, and that the operator wishes to. converse with subscriber B, listening key 5 is'actuated'to, connect the operators telephone set with the calling end ofthe cord circuit C and the answering end thereof is simultaneously short-circuited. The circuit including the operators tele phone set established by the actuation of the listening key 5, may be traced from the tip conductor of the calling plug 6 through thextip talking strand v7,-conductor 8, contact 9, conductors l0 and ll, the operators telephone'set,conductor 12, contact, 13, portion ld-of the ring talking strand, contact 15 of'listeningkey16,.portion 35 ofthe ring talking strandvto' the ring contact of the calling plug 6. The short circuit for the answering end of the cord circuit established by 'the actuation :of' key 5, may be traced from the point 80 on the tip talking strand through the contact 25 of the listening key 5 to the point'81 on the ring talking strand. It. will be'observe'd that battery for talking purposes is now fed through the double-wound retardation coil 27 to the callciated withcord circuit C is energized upon the actuation ofthe listening key 5 and cooperates with a similar relay of another cord circuit when energized to establish a short circuit for the operators telephone set, as will hereinafter more fully appear. Should the operator desire to converse with subscriber A rather than subscriber B, the listening key 16 instead of5 is actuated to thereby connect the operators telephone set with the answering end of the cord circuit and tosimultaneously establish a short circuit for the calling end thereof. The'circuit including operators telephone .set, established by the actuation of the listening key 16, may be traced from thetip contact of the answering plug 4,-tip talking strand .7, contact 31" of the listening key 16, conductors 10 and '11, the operators telephone set, conductor 12, contact 32 of the listening Ekey 16, portion 14' of the ring talkingstrand, contact33 of the listening key 5, portion 26 of the ringtalkin'g strand to. the ring contact of the answering. plug.

I With" this condition of the cord circuit, the

battery for talking purposes is'fed through the listening key 16 to the point 83 on the ring talking strand. Relay 30 is also operated upon the actuation of the listening key 16.

Between the lines 22- and 3 3 .in,Fig.,

1, there is shown a relay 40 similar in all respects to relay 30, which} is associated V with another cord circuit and is actuated when either of the listening, keys of this other cord circuit'is actuated. Below the line 33 in F ig. 1, thereis shown another relay 50 similar to relays 30 andglO, which is associatedwitha thirdcord circuit similar to the cord circuit C.

If the answering end of cord circuit, C be, connected withone telephonev lineand the answering end of another cord circuit with which relay 40' is associated; be connected to another telephone line and-anattempt be made to connect these lines, together by actuating one of the listenmg keys in each cord circuit, the lines arenot thereby connected telephonically, together but the operators telephone. set is, immediately short-circuited.- This is brought about by the energizationof relays 30x and 40 when a listening key of: cord circuit C and a listening key of-thecord-circuit with which relay LO-is associated: are actuated. The short circuit for the operatofis telephone set may be traced from a point 41 through conductoretQ, contact 13 of relay 30, contact 4 1 of relay 10, andcontact 45 of relay 3O to a. pointeLS. If relay 50instead of 4L0 had been energized at timerrelay 30 was energized, the short circuit for the operators telephone set established thereby, would be from the point 41 through conductor 42, contact 430i relay. 30, contact 1-7 of relay 40, contact 18 of relay 50, andcontact 15 of relay'80 "to the point 46;

In Fig- 2 there isshown a. cord circuit provided with apparatus forshort-circuiting one end of the cord circuit whenever the" operators telephone set is associated with the other end. In this cord circuit, the. number be key contacts; has! been. reduced and the connection" of: the operators telephone setto one end ot tlie cord circuit and: the simultaneous short-circuitingofthe other end is efiected fthroughl'theoperationof relays controlled. by single c contactkeys.

Referring further to the cord circuit, of Fig. 2 and assuming that the answering end thereof; is connected with the answering jack of linecA that the callingtend I is; connected with the answering-jack ot, line- B,

' and that the operator wishingrto converse with subscriber B actuates key 51, relay, 53

is thereupon energized. The energization of relay 53 causes this relay to open. its normal contact 54 and to connect the operators telephone set through its left-hand alternate contacts57;and 58 to the calling end of the cord circuit.- The, closure of the right alternate contact of relay 53 estab- The circuit including of relay, 5,3, the operatons; telephone set, '7

contact; 58.0f; relay 5 3, and portionsh? and 68,015 thering talking strand to th ezring contact of the. calling,- plug; 66. The short circuit for, the {answering-lend I resulting from the actuation of the key 51maybe traced from the point; 7 0 on; the tip talkingstrand through therighthand alternate contact to relay 53, andtheright hand normallcontact ofrelay 55;to the point 71,0 11 the ringta lke ing, strand. Battery for talking purposes is. now fed; to ,the; calling end of, the cord circuit thrQ gh heldouble wound retardation coil 61 and the left-hand normal contact Of relay lfith'e operator desires to converse.,-with subscriber A instead of subscriber B,- key 52 instead of5 lris actuated. The actuation of; key; 52 causesthe; energization of relays 5-3 and 55, thereby connecting the ,operators telephone set with the answering end of the cord circuit and simultaneously short-circuiting the calling end thereof. The oircuit includingthe operators telephone set may, be traced from thetip contact of-the answering plug Gfhthrough thetip talking strand 67, right;hand alternate contact of relay53, right handalternate contatofrelay 55,1 the,por tion 59 of-the ring talking strand, contact 58 of relay 53 the operatorstelephorwset, contact 5? of relay'53, and portions 56 1 and 60 of the, ring talking strand to the ringcontact of the answering plugtil. The shqrtcirc'uit for the calling end may beitracedtfronrthe point 70,611 the tip xtalking strand through the -right;hand alternate contact of relay- 53, andthe righthand alternate contact 55'' to the point 7 2 on, the ring,talki'ng strand. Batteryifor ltalking piirpqses{is now fed to, I the answeringend off the, cord cireuit'i through the double wound retardation coil: 61 and i operatorrs telephone set to oneriend thereof while the other end is simultaneously shortcircuited. I e 7 What is claimed-is:

1', A telephone exchange system comprising two telephone lines, a connecting Cir cuit joining the lines, an operators telephone set, an operator controlled switch the connecting circuit established upon the actuation of the switch.

2. A telephone exchange system comprising two telephone lines, a connecting circuit joining the lines, an operators telephone set, a listening key actuated to connect the operators telephone set with one end of the connecting circuit, and a short circuit for the other end of the connecting circuit established by the actuation of the listening key and including a contact thereof.

3. A telephone exchange system comprising telephone lines terminating at a central oilice, connecting circuits thereat for interconnecting the lines, an operators telephone set, an operator-controlled switch for each connecting circuit adapted when actuated to cause the connection of an operators telephone set with the corresponding connecting circuit, a relay for each connecting circuit operating upon the actuation of the associated switch, and a disabling circuit for the operators telephone set established upon the simultaneous operation of two relays.

l. A telephone exchange system comprising telephone lines terminating at a central otiice, connecting circuits thereat for inter connecting the lines, an operators telephone set, a listening key for each connecting circuit adapted when actuated to connect the operators telephone set with the connecting circuit, a relay for each connecting circuit energized upon the actuation of the associated listening key, and a short circuit for the operators telephone set established by the simultaneous energization of two relays and including contacts of both relays.

5. A. telephone exchange system comprising telephone lines terminating at a central office, connecting circuits thereat for inter connecting the lines, an operators telephone set, an operator controlled switch for each connecting circuit adapted when actuated to connect'the operators telephone set with one end of the associated connecting circuit, a short circuit for the other end of the associated connecting circuit established upon the actuation of the switch, a relay for each connecting circuit operating upon the actuation of the switch associated therewith, and a disabling circuit for the operators telephone set established .upon the simultaneous operation of two relays.

6. A telephone exchange system comprising telephone lines terminating at a central office, connecting circuits thereat for inter-' connecting the lines, an operators telephone set, a listening key for each connecting circuit actuated to connect the operators telephone set with one end thereof, a short circuit for the other end of the connecting circuit established by the actuation of the listening" key and including a contact thereof, arelay for each connecting circuit energized upon the actuation of the listening key, and a short circuit for an operators telephone set established by the simulta neous energization of two relays and including contacts of both relays.

In witness whereof I hereunto subscribe my name this 9th day of July, A. D. 1917.

CHARLES W. KECKLER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. G. 

